Photometric Variability of the Be Star Population
Photometric Variability of the Be Star Population
复制标题
Be Star 群体的光度变异性
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
T. Beatty
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作者：
J. Labadie;J. Pepper;M. McSwain;J. Bjorkman;K. Bjorkman;M. Lund;Joseph E. Rodriguez;K. Stassun;D. Stevens;D. James;R. Kuhn;R. Siverd;T. Beatty
Be星通常以其光谱中的发射线为特征，特别是这些光谱特征的时间变异性。众所周知，它们在多个时间尺度上也表现出光度可变性，但还没有被广泛地比较和分析。我们利用了寻找凌日系外行星的广视场、长基线和高节奏光度测量的出现，对大量已知的Be恒星的亮度变化进行了全面的分析。测光数据来自KELT凌日调查，典型的节奏为30分钟，基线长达10年，测光精度约1%，覆盖约60%的天空。我们分析了北半球和南半球610颗已知Be星的KELT光曲线，以努力研究它们的可变性。与其他关于BE恒星可变性的研究一致，我们发现大多数恒星在光度上是可变的。我们得出了样本中表现出与非径向脉动(25%)、爆发(36%)和星盘长期趋势(37%)一致的特征的恒星比例的下限，并展示了这些与光谱亚型的关联。还探讨了其他类型的可变性，例如由二进制引起的可变性。Be恒星光谱数据库中的一些系统的同步光谱学使我们能够更好地了解观测到的变化的物理原因，特别是在爆发和盘中变化的情况下。
Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.